This section introduces the reader to various aspects of art, which may be associated with embodiments of the present invention. This discussion is helpful in providing the reader with information to facilitate a better understanding of particular techniques of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not necessarily as admissions of prior art.
The world is running out of potable fresh water. Worldwide, an estimated 700 million people cannot obtain enough clean water. In the next 10 years, the number is projected to increase to approximately 1.8 billion people. In some regions, obtaining fresh water from seawater may be the only viable way to increase supply of fresh water.
Parts of the West coast of the United States, especially California, has been in a severe long-term drought. This long-term drought has stressed the water resources of the region. The environmental damage includes damage to the ecology and hydrology from diminishing groundwater and acquirer water resources that are being excessively depleted to provide the water requirements of individuals, agriculture and industry. Furthermore, the lack of sufficient water supply is hurting the economy by forcing the region to charge more for water resources and shutting down some water intensive industries and businesses.
In the past, desalination plants have been proposed to resolve the fresh water resources problem. Reverse osmosis (“RO”) plants have been delivering desalinated water for decades to regions with limited water resources. However, the high cost to build and operate the RO plants historically made the plants uneconomical for most regions. Accordingly, the major issue of RU technology is that it costs too much. The RU process requires significant energy to force salt water against polymer membranes that have pores small enough to let fresh water through while holding salt ions back.
New plants, using innovative technology, such as, the Sorek plant in Israel have significantly reduced the cost per cubic volume versus conventional desalination plants. The Sorek plant, with a capacity of over 150 million gallons per day of desalinated water, has significantly reduced energy consumption through technological advances and economics of scale using scalable designs. For example, the Sorek plant incorporates a number of engineering improvements to increase efficiencies over previous RO facilities. This technology includes utilizing larger pressure tubes that are 16 inches in diameter rather than eight inches. The larger pressure tubes require only a fourth as much piping and other hardware, slashing costs. The facility uses highly efficient pumps and energy recovery devices. In addition, new technologies are being developed such as, advanced membranes made of atom-thick sheets of carbon, which hold the promise of further cutting the energy requirements of desalination plants.
While this technology has unproved the economics of RO desalination, there are still many additional problems to be solved. One problem is the lack of available waterfront land in many regions from over development along the coastlines and developmental restrictions including Not-In-My-Backyard or “NIMBYism.” Offshore desalination has been proposed and desalination has been done on ships. There have been proposals to construct large-scale desalination plants on barges or offshore structures.
However, the barges, ships and offshore structures being proposed are difficult to install and are not designed to effectively handle large scale desalination. Accordingly. there is a need for an of shores structure apparatus, system and method that facilitates efficient setup of large scale desalination units that can efficiently purify large volumes of water. Embodiments of the invention disclosed herein satisfies these needs.
The disposal of the highly-concentrated salt brine that contains other chemicals used throughout the process has become a major environmental issue. Large coastal seawater desalination plants discharge brine into oceans and estuaries and therefore, technologies must be developed to provide safe disposal and/or discharge of brine effluent. Typically, twice as saline as the ocean, the brine discharge is denser than the waters into which it is discharged into and thus, usually sinks and slowly spreads along the ocean floor, where there is typically minimal wave energy or currents to mix discharge. There are several proven methods to disperse concentrated brine, such as multi-port diffusers placed on the discharge pipe to promote mixing or injecting the discharge brine below the seafloor. Discharge brine can also be diluted with effluent from a wastewater treatment plant or with cooling water from a power plant or other industrial user. Unfortunately. these approaches have not been shown to sufficiently reduce the brine concentration enough to prevent serious harm to marine life surrounding the discharge point source.
Accordingly, there is a need to provide offshore desalination, with the ability to efficiently reduce the salinity of the effluent brine discharge to avoid environmental issues to marine ecosystems, including killing marine organisms. In addition, there is a need to further reduce the operating costs by reducing the amount of power needed and reducing the number of necessary personnel. In addition to desalination, there is a need to dilute offshore wastewater for maritime, offshore, and nearshore industrial activities. The multiple apparatus, method and system embodiments, disclosed herein, can solve these needs.
In one embodiment, an apparatus is disclosed. In this embodiment, the apparatus comprises: a structure (such as, an offshore structure), wherein the offshore structure comprises a water intake device connected to a plurality of filters connected to a plurality of reverse osmosis filters in communication with a purified water line and effluent discharge device. A plurality of filters moves the water from the intake and then through the reverse osmosis membranes to the discharge device and purified water lines.
In another embodiment, a method is disclosed. In this embodiment, the method comprises obtaining a structure comprising a water purification system; flowing water into an inlet device: pumping the water through a filtration system: flowing the filtered water through a plurality of reverse osmosis filters; flowing purified water through a purified water line: and flowing discharge effluent through a discharge device that mixes the discharge with seawater before point discharge.
In another embodiment, a system is disclosed. This system comprises a structure. The structure comprises a water intake device connected to a plurality of filters that are connected to a plurality of reverse osmosis membranes in communication with a purified water line and effluent discharge device: and a control panel that controls, the pumps, filters, reverse osmosis membranes and discharge devices. In a more specific embodiment. the system controls the discharge device to achieve favorable mixing of the discharged water and the water from the inlet, electrical generation. or combinations thereof.